Compositions containing fluorine substituted olefins

Disclosed are heat transfer compositions, and methods of using and selecting heat transfer compositions, in which the composition comprises a first component comprising difluoromethane (R-32), and at least one second component selected from group consisting of CF3I, 1,2,3,3,3-pentafluoropropene (HFO 1225ye), and combinations of these, and optionally, but preferably, at least one third component selected from the group consisting of fluorinated C2-C3 compounds, including any combination of two or more fluorinated C2-C3 compounds.

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Description
RELATED APPLICATIONS

The present application is related to and claims the priority benefit of each of the following U.S. application Ser. Nos. 11/475,605, filed Jun. 26, 2006; 10/837,525, filed Apr. 29, 2004; and 10/694,273, filed Oct. 27, 2003, each of which is pending and incorporated herein by reference.

The present application is also related to, claims the priority benefit of, and incorporates by reference each of the following U.S. application Ser. Nos. 11/385,259, filed Mar. 20, 2006, now pending, which in turn claims the benefit of 10/695,212, which was filed Oct. 23, 2003, now abandoned; and 11/757,782, filed Jun. 4, 2006, pending, which in turn claims the priority benefit of 10/694,272 filed Oct. 27, 2003, pending.

FIELD OF THE INVENTION

This invention relates to compositions having utility in numerous applications, including particularly refrigeration systems, and to methods and systems utilizing such compositions. In preferred aspects, the present invention is directed to refrigerant compositions comprising difluoromethane and at least one multi-fluorinated olefin and/or at least one fluoroiodocarbon.

BACKGROUND OF THE INVENTION

Fluorocarbon based fluids have found widespread use in many commercial and industrial applications. For example, fluorocarbon based fluids are frequently used as a working fluid in systems such as air conditioning, heat pump and refrigeration applications. The vapor compression cycle is one of the most commonly used type methods to accomplish cooling or heating in a refrigeration system. The vapor compression cycle usually involves the phase change of the refrigerant from the liquid to the vapor phase through heat absorption at a relatively low pressure and then from the vapor to the liquid phase through heat removal at a relatively low pressure and temperature, compressing the vapor to a relatively elevated pressure, condensing the vapor to the liquid phase through heat removal at this relatively elevated pressure and temperature, and then reducing the pressure to start the cycle over again.

Certain fluorocarbons have been a preferred component in many heat exchange fluids, such as refrigerants, for many years in many applications. For, example, fluoroalkanes, such as chlorofluoromethane and chlorofluoroethane derivatives, have gained widespread use as refrigerants in applications including air conditioning and heat pump applications owing to their unique combination of chemical and physical properties. Many of the refrigerants commonly utilized in vapor compression systems are either single components fluids or azeotropic mixtures.

Concern has increased in recent years about potential damage to the earth's atmosphere and climate, and certain chlorine-based compounds have been identified as particularly problematic in this regard. The use of chlorine-containing compositions (such as chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and the like) as refrigerants in air-conditioning and refrigeration systems has become disfavored because of the ozone-depleting properties associated with many of such compounds. There has thus been an increasing need for new fluorocarbon and hydrofluorocarbon compounds and compositions that offer alternatives for refrigeration and heat pump applications. For example, it has become desirable to retrofit chlorine-containing refrigeration systems by replacing chlorine-containing refrigerants with non-chlorine-containing refrigerant compounds that will not deplete the ozone layer, such as hydrofluorocarbons (HFCs).

Another concern surrounding many existing refrigerants is the tendency of many such products to cause global warming. This characteristic is commonly measured as global warming potential (GWP). The GWP of a compound is a measure of the potential contribution to the green house effect of the chemical against a known reference molecule, namely, CO2 which has a GWP=1. For example, the following known refrigerants possess the following Global Warming Potentials:

REFRIGERANT GWP R410A 1975 R-507 3850 R404A 3784 R407C 1653

While each of the above-noted refrigerants has proven effective in many respects, these material are become increasingly less preferred since it is frequently undesirable to use materials having GWPs greater than about 1000. A need exists, therefore, for substitutes for these and other existing refrigerants having undesirable GWPs.

It is generally considered important, however, that any potential substitute refrigerant must also possess those properties present in many of the most widely used fluids, such as excellent heat transfer properties, chemical stability, low- or no-toxicity, non-flammability and lubricant compatibility, among others.

With regard to efficiency in use, it is important to note that a loss in refrigerant thermodynamic performance or energy efficiency may have secondary environmental impacts through increased fossil fuel usage arising from an increased demand for electrical energy.

Furthermore, it is generally considered desirable for refrigerant substitutes to be effective without major engineering changes to conventional vapor compression technology currently used with existing refrigerants, such as CFC-containing refrigerants.

Flammability is another important property for many applications. That is, it is considered either important or essential in many applications, including particularly in heat transfer applications, to use compositions which are non-flammable. Thus, it is frequently beneficial to use in such compositions compounds which are nonflammable. As used herein, the term “nonflammable” refers to compounds or compositions, which are determined to be nonflammable as determined in accordance with ASTM standard E-681, dated 2002, which is incorporated herein by reference. Unfortunately, many HFCs, which might otherwise be desirable for used in refrigerant compositions are not nonflammable. For example, the fluoroalkane difluoroethane (HFC-152a) and the fluoroalkene 1,1,1-trifluoropropene (HFO-1243zf) are each flammable and therefore not generally desirable when used alone in many applications.

Applicants have thus come to appreciate a need for compositions, and particularly heat transfer compositions, that are potentially useful in numerous applications, including vapor compression heating and cooling systems and methods, while avoiding one or more of the disadvantages noted above.

SUMMARY

Applicants have found that the above-noted need, and other needs, can be satisfied by compositions comprising, and preferably consisting essentially of difluoromethane (R-32), and a second component selected from group consisting of CF3I, 1,2,3,3,3-pentafluoropropene (HFO 1225ye), and combinations of these, and optionally, but preferably, at least one third component selected from the group consisting of fluorinated C2-C3 compounds, including any combination of two or more fluorinated C2-C3 compounds. As used herein, the term “fluorinated C2-C3 compounds” means organic molecules having 2 or 3 carbon atoms and at least one fluorine substituent.

In certain preferred embodiments, the second component is a flammability reducing agent. As used herein, the term flammability reducing agent refers to a compound or combination of compounds having the net effect of reducing the flammability of the composition relative to the flammability of difluoromethane alone.

In certain preferred embodiments, the third component is selected from the group consisting of fluorinated ethanes, fluorinated alkenes (preferably fluorinated propylenes), and combinations of any two or more of these.

The present invention provides also methods and systems which utilize the compositions of the present invention, including methods and systems for transferring heat, and methods and systems for replacing an existing heat transfer fluid in an existing heat transfer system, and methods of selecting a heat transfer fluid in accordance with the present invention to replace one or more existing heat transfer fluids. In preferred embodiments, the methods and systems for selecting a replacement heat transfer fluid comprise selecting a heat transfer fluid to replace one or more of the following heat transfer fluids in an existing heat transfer system: R-22, R-404A, R-407C, R-410A, R-507, and combinations of any two or more of these.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-12 are ternary composition curves for certain preferred compositions of the present invention at various concentrations of each component for which the capacity substantially matches a known refrigerant, as described in the Examples hereof.

 DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The Compositions

The present invention is directed, in one aspect, to compositions comprising a first component consisting essentially of difluoromethane (HFC-32). It is contemplated that the amount of HFC-32 present may vary widely within the broad scope of the present invention. In preferred embodiments, the amount of HFC-32 present in the composition is selected based on the desired heat transfer capacity of the fluid, based typically on the system in which the fluid will be used or is present. For embodiments in which the composition is used or intended for use in a system originally designed for use with one or more of R-22, R-404A, R-407C, R-410A, R-507 (hereinafter referred to for purposes of convenience but not by way of limitation as the “existing refrigerant group”), the difluoromethane is preferably present in the composition in an amount of from about 1 wt % to about 60 wt %, more preferably from about 5 wt % to about 55 wt %, and even more preferably form about 10 wt % to about 50 wt %.

In certain preferred embodiments, the first component further comprises CO2, preferably in amounts of not greater than about 5 wt % of the composition.

The second component of the present compositions may also vary widely within the broad scope of the present invention. In preferred embodiments, the particular second component and its amount in the composition are selected based on the ability to reduce the flammability of the overall composition. For embodiments in which the composition is used or intended for use in a system originally designed for use with one or more of the refrigerants in the existing refrigerant group, the second component is preferably present in the composition in an amount of from about 5 to about 99 percent by weight of the composition. In other preferred embodiments, the second component is present in amounts for from about 1 to about 65 percent by weight of the composition.

The amount of the third component may also vary widely within the broad scope of the present invention. In preferred embodiments, the amount of the third component present in the composition is also selected based on the desired heat transfer properties, particularly and preferably the heat capacity, of the composition, and all such amounts are within the scope of the present invention. The third component of the present invention in certain preferred embodiments is present in the heat transfer composition in amounts of from about 1 to about 99 percent by weight of the composition.

As mentioned above, the third component is preferably selected from the group consisting of fluorinated ethanes, fluorinated alkenes (preferably fluorinated propylenes), and combinations of any two or more of these. Particularly preferred from among the fluorinated ethanes are monofluoroethane (HFC-161), difluoroethane (HFC-152a), trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC-134a), and pentafluoroethane (HFC-125). The fluoroalkene compounds of the present invention are sometimes referred to herein for the purpose of convenience as hydrofluoro-olefins or “HFOs” if they contain at least one hydrogen. Although it is contemplated that the HFOs of the present invention may contain two carbon—carbon double bonds, such compounds at the present time are not considered to be preferred.

In certain preferred embodiments, the present compositions comprise one or more compounds in accordance with Formula I. In preferred embodiments, the compositions include compounds of Formula I below:

where each R is independently Cl, F, Br, I or H

R′ is (CR2)nY,

Y is CRF2

and n is 0 or 1, it being generally preferred however that when Br is present in the compound there is no hydrogen in the compound. In certain embodiments, Br is not present in the compound.

In highly preferred embodiments, Y is CF3, n is 0 or 1 (most preferably 0) and at least one of the remaining Rs is F, and preferably no R is Br or when Br is present, there is no hydrogen in the compound.

Applicants believe that, in general, the compounds of the above identified Formula I generally effective and exhibit utility in refrigerant compositions; however, it has been surprisingly and unexpectedly found that certain of the compounds having a structure in accordance with the formulas described above exhibit a highly desirable low level of toxicity compared to other of such compounds. As can be readily appreciated, this discovery is of potentially enormous advantage and benefit for the formulation of not only refrigerant compositions, but also any and all compositions, which would otherwise contain relatively toxic compounds satisfying the formulas described above. More particularly, applicants believe that a relatively low toxicity level is associated with compounds of Formula I, preferably wherein Y is CF3, wherein at least one R on the unsaturated terminal carbon is H and/or at there is not more than one F on the unsaturated terminal carbon. Applicants believe also that all structural, geometric and stereoisomers of such compounds are effective and of beneficially low toxicity.

In certain embodiments it is highly preferred that the compounds of Formula I comprise propenes having from 3 to 5 fluorine substituents, with other substituents being either present or not present. In certain preferred embodiments, no R is Br, and preferably the unsaturated radical contains no Br substituents.

Among the propenes, tetrafluoropropenes (HFO-1234) and pentafluoropropenes are preferred, including particularly those pentafluoropropenes in which there is a hydrogen substituent on the terminal unsaturated carbon, such as CF3CF═CFH(HFO-1225yez and/or yz), particularly since applicants have discovered that such compounds have a relatively low degree of toxicity in comparison to at least the compound CF3CH═CF2 (HFO-1225zc). In highly preferred embodiments, especially embodiments comprising the low toxicity compounds described above, n is zero. In certain highly preferred embodiments the compositions of the present invention comprise one or more tetrafluoropropenes. The term “HFO-1234” is used herein to refer to all tetrafluoropropenes. Among the tetrafluoropropenes, both cis- and trans-1,3,3,3-tetrafluoropropene (HFO-1234ze) are particularly preferred. The term “HFO-1225” is used herein to refer to all pentafluoropropenes. Among such molecules are included 1,1,1,2,3 pentafluoropropene (HFO-1225yez), both cis- and trans-forms thereof. The term HFO-1225yez is thus used herein generically to refer to 1,1,1,2,3 pentafluoropropene, independent of whether it is the cis- or trans-form. The term “HFO-1225yez” therefore includes within its scope cis HFO-1225yez, transHFO-1225yez, and all combinations and mixtures of these.

The term HFO-1234ze is used herein generically to refer to 1,3,3,3-tetrafluoropropene, independent of whether it is the cis- or trans-form. The terms “cis HFO-1234ze” and “transHFO-1234ze” are used herein to describe the cis- and trans-forms of 1,3,3,3-tetrafluoropropene respectively. The term “HFO-1234ze” therefore includes within its scope cis HFO-1234ze, transHFO-1234ze, and all combinations and mixtures of these.

Although the properties of cis HFO-1234ze and transHFO-1234ze differ in at least some respects, it is contemplated that each of these compounds is adaptable for use, either alone or together with other compounds including its stereoisomer, in connection with each of the applications, methods and systems described herein. For example, while transHFO-1234ze may be preferred for use in certain refrigeration systems because of its relatively low boiling point (−19° C.), it is nevertheless contemplated that cis HFO-1234ze, with a boiling point of +9° C., also has utility in certain refrigeration systems of the present invention. Accordingly, it is to be understood that the terms “HFO-1234ze” and 1,3,3,3-tetrafluoropropene refer to both stereo isomers, and the use of this term is intended to indicate that each of the cis- and trans-forms applies and/or is useful for the stated purpose unless otherwise indicated.

HFO-1234 compounds are known materials and are listed in Chemical Abstracts databases. The production of fluoropropenes such as CF3CH═CH2 by catalytic vapor phase fluorination of various saturated and unsaturated halogen-containing C3 compounds is described in U.S. Pat. Nos. 2,889,379; 4,798,818 and 4,465,786, each of which is incorporated herein by reference. EP 974,571, also incorporated herein by reference, discloses the preparation of 1,1,1,3-tetrafluoropropene by contacting 1,1,1,3,3-pentafluoropropane (HFC-245fa) in the vapor phase with a chromium-based catalyst at elevated temperature, or in the liquid phase with an alcoholic solution of KOH, NaOH, Ca(OH)2 or Mg(OH)2. In addition, methods for producing compounds in accordance with the present invention are described generally in connection with pending United States patent application entitled “Process for Producing Fluoropropenes” bearing attorney docket number (H0003789 (26267)), which is also incorporated herein by reference.

The present compositions, particularly those comprising HFO-1234ze, are believed to possess properties that are advantageous for a number of important reasons. For example, applicants believe, based at least in part on mathematical modeling, that the fluoroolefins of the present invention will not have a substantial negative affect on atmospheric chemistry, being negligible contributors to ozone depletion in comparison to some other halogenated species. The preferred compositions of the present invention thus have the advantage of not contributing substantially to ozone depletion. The preferred compositions also do not contribute substantially to global warming compared to many of the hydrofluoroalkanes presently in use.

In certain preferred forms, compositions of the present invention have a Global Warming Potential (GWP) of not greater than about 1000, more preferably not greater than about 500, and even more preferably not greater than about 150. In certain embodiments, the GWP of the present compositions is not greater than about 100 and even more preferably not greater than about 75. As used herein, “GWP” is measured relative to that of carbon dioxide and over a 100-year time horizon, as defined in “The Scientific Assessment of Ozone Depletion, 2002, a report of the World Meteorological Association's Global Ozone Research and Monitoring Project,” which is incorporated herein by reference.

In certain preferred forms, the present compositions also preferably have an Ozone Depletion Potential (ODP) of not greater than 0.05, more preferably not greater than 0.02 and even more preferably about zero. As used herein, “ODP” is as defined in “The Scientific Assessment of Ozone Depletion, 2002, A report of the World Meteorological Association's Global Ozone Research and Monitoring Project,” which is incorporated herein by reference.

In general, the preferred heat transfer compositions of the present invention are zeotropic over much, and potentially over the entire, range of temperatures and pressures of use. That is, the mixtures of the components produce a liquid with a non-constant boiling temperature, therefore producing what is know as a “temperature glide” in the evaporator and condenser. The “temperature glide” is the change in temperature that occurs as a zeotropic material condenses or evaporates. This glide is preferably considered in connection with the method and composition aspects of the present invention in order to provide a composition which most effectively matches the refrigerant composition being replaced. In a single component or azeotropic mixture the temperature glide is 0. R-407C is a zeotropic mixture that has a 5° C. glide in typical applications, and in certain preferred embodiments, the present compositions produce a temperature glide of about 5° C. under conditions of actual or contemplated use.

The compositions of the present invention may include other components for the purpose of enhancing or providing certain functionality to the composition, or in some cases to reduce the cost of the composition. For example, refrigerant compositions according to the present invention, especially those used in vapor compression systems, include a lubricant, generally in amounts of from about 30 to about 50 percent by weight of the composition. Furthermore, the present compositions may also include a compatibilizer, such as propane, for the purpose of aiding compatibility and/or solubility of the lubricant. When present, such compatibilizers, including propane, butanes and pentanes, are preferably present in amounts of from about 0.5 to about 5 percent by weight of the composition. Combinations of surfactants and solubilizing agents may also be added to the present compositions to aid oil solubility, as disclosed by U.S. Pat. No. 6,516,837, the disclosure of which is incorporated by reference. Commonly used refrigeration lubricants such as Polyol Esters (POEs) and Poly Alkylene Glycols (PAGs), silicone oil, mineral oil, alkyl benzenes (ABs) and poly(alpha-olefin) (PAO) that are used in refrigeration machinery with hydrofluorocarbon (HFC) refrigerants may be used with the refrigerant compositions of the present invention.

Many existing refrigeration systems are currently adapted for use in connection with existing refrigerants, and the compositions of the present invention are believed to be adaptable for use in many of such systems, either with or without system modification. In many applications the compositions of the present invention may provide an advantage as a replacement in systems, which are currently based on refrigerants having a relatively high capacity. Furthermore, in embodiments where it is desired to use a lower capacity refrigerant composition of the present invention, for reasons of cost for example, to replace a refrigerant of higher capacity, such embodiments of the present compositions provide a potential advantage. In certain applications, the refrigerants of the present invention potentially permit the beneficial use of larger displacement compressors, thereby resulting in better energy efficiency than other refrigerants, such as HFC-134a. Therefore the refrigerant compositions of the present invention, particularly compositions comprising transHFP-1234ze, provide the possibility of achieving a competitive advantage on an energy basis for refrigerant replacement applications.

It is contemplated that the compositions of the present, including particularly those comprising HFO-1234ze, also have advantage (either in original systems or when used as a replacement for refrigerants), in chillers typically used in connection with commercial air conditioning systems.

The present methods, systems and compositions are thus adaptable for use in connection with automotive air conditioning systems and devices, commercial refrigeration systems and devices, chillers, residential refrigerator and freezers, general air conditioning systems, heat pumps, and the like.

Particularly preferred embodiments of the compositions of the present invention are described below.

HFC-32/CF3I Based Compositions

In one preferred embodiment of the present invention, the compositions comprise a first component which comprises in major proportion, and preferably consists essentially of, and even more preferably consists of, HFC-32. In such embodiments, it is generally preferred that the amount of the HFC-32 present in the composition is from about 1 to about 60 percent by weight of the composition.

The compositions in such preferred embodiments also comprise a second component comprising CF3I. In certain of such embodiments, the second component comprises CF3I in major proportion, and preferably consists essentially of, and even more preferably consists of, CF3I. The amount of CF3I present in the composition is preferably from about 5 to about 98 percent by weight of the composition. For those embodiments in which the second component comprises both CF3I and HFO-1225, the relative amount of CF3I and HFO-1225 can vary widely, but it is preferred in such embodiments that the amount of CF3I is from about 5 to about 98 percent by weight of the composition and the amount of HFO-1225 is from about 1 to about 65 percent by weight of the composition. For embodiments in which the second component comprises CF3I and HF01225, the third component is optional, but if present, is preferably present in an amount of from about 1 to 94 percent by weight of the composition. In embodiments in which the second component consists essentially of CF3I, that is, the composition does not include a substantial amount of HFO-1225, the third component is required and is preferably present in the composition in an amount of at least about 1 percent by weight of the composition.

It is contemplated that a large number of combinations of compounds may be used as the third component of the present invention in this particular embodiment, and in a wide variety of relative concentrations, and all amounts and combinations are believed to be adaptable for use in accordance with the teachings contained herein. In certain preferred embodiments, however, wherein the third component comprises one or more of monofluoroethane (HFC-161), difluoroethane (HFC-152a), trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC-134a), pentafluoroethane (HFC-125), 1,1,1,3-tetrafluoropropene (HFO-1234ze, including all isomers) and 1,1,1,2-tetrafluoropropene (HFO-1234yf), it is preferred that, if present, such components are selected from within the ranges indicated in the following Table 1 (indicated amounts are intended to be understood to be preceded by the modifier “about” and are based on the weight percentage in the composition):

TABLE 1 THIRD COMPONENT↓ WEIGHT PERCENTAGE R-152a 1-65 R-134a 1-70 1234ze 1-80 1234-yf 1-80 R-125 1-30 R-161 1-94 R-143a 1-20

HFC-32/HFO-1225 Based Compositions

In these embodiments of the present invention, the compositions comprise a first component which comprises in major proportion, and preferably consists essentially of, and even more preferably consists of, HFC-32. In such embodiments, it is generally preferred that the amount of the HFC-32 present in the composition is from about 1 to about 60 percent by weight of the composition.

The compositions in such preferred embodiments also comprise a second component comprising HFO-1225, preferably HFO-1225ye-Z. In certain of such embodiments, the second component comprises HFO-1225 in major proportion, and preferably consists essentially of, and even more preferably consists of, HFO-1225ye-Z. The amount of HFO-1225ye-Z present in the composition is preferably from about 5 to about 98 percent by weight of the composition. In such embodiments, the third component is optional, but if present, is preferably present in an amount of from about 1 to 94 percent by weight of the composition.

It is contemplated that a large number of combinations of compounds may be used as the third component of the present invention in this particular embodiment, and in a wide variety of relative concentrations, and all amounts and combinations are believed to be adaptable for use in accordance with the teachings contained herein. In certain preferred embodiments, however, wherein the third component comprises one or more of monofluoroethane (HFC-161), difluoroethane (HFC-152a), trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC-134a), pentafluoroethane (HFC-125), 1,1,1,3-tetrafluoropropene (HFO-1234ze, including all isomers) and 1,1,1,2-tetrafluoropropene (HFO-1234yf), it is preferred that, if present, such components are selected from within the ranges indicated in the following Table 2 (indicated amounts are intended to be understood to be preceded by the modifier “about” and are based on the weight percentage in the composition)

TABLE 2 THIRD COMPONENT↓ WEIGHT PERCENTAGE R-152a 1-65 R-134a 1-70 1234ze 1-80 1234-yf 1-80 R-125 1-30 R-161 1-94 R-143a 1-20

The Selection Methods

One aspect of the present invention involves methods for selecting a heat transfer composition for use in connection with an existing heat transfer system. As used herein, the term “existing heat transfer system” includes not only actual heat transfer systems that have been built and are in place but also systems that are not yet built but are being conceived and/or are in the design phase. One preferred embodiment provides methods for selecting a heat transfer composition for use in connection with an existing heat transfer system that has been designed for use in connection with a previously known composition. In such cases, the previously known composition will generally have a desired or expected heat capacity but will also exhibit one or more undesirable properties. For example, each of the following previously known refrigerants have desirably heat capacities for the systems in which they are being used but also exhibit the undesirably high GWP as indicated:

REFRIGERANT GWP R134a 1300 R125 3400 R143a 4300

The preferred method steps comprise analyzing the parameters of the system in a manner sufficient to permit approximation of the capacity of the existing or design heat transfer fluid and providing a tool that permits approximation of the capacity of two or more compositions of the present invention at the conditions of existing or design system, and utilizing said to select a composition for use in the existing or design system. Examples of such a tool are the charts illustrated in the Examples below. A computer program, configured in accordance with the teachings contained herein, is an example of another such tool. In preferred embodiments, the tool also is able to approximate, determine or incorporate the GWP and/or the flammability of the composition of the present invention and the selection step comprises selecting the composition so as to have a GWP of less than about 1000, and even more preferably less than about 150, and/or to have no flammability or flammability within a predetermined parameter.

Heat Transfer Methods and Systems

The compositions of the present invention are useful in connection with numerous methods and systems, including as heat transfer fluids in methods and systems for transferring heat, such as refrigerants used in refrigeration, air conditioning and heat pump systems.

The preferred heat transfer methods generally comprise providing a composition of the present invention and causing heat to be transferred to or from the composition changing the phase of the composition. For example, the present methods provide cooling by absorbing heat from a fluid or article, preferably by evaporating the present refrigerant composition in the vicinity of the body or fluid to be cooled to produce vapor comprising the present composition. Preferably the methods include the further step of compressing the refrigerant vapor, usually with a compressor or similar equipment to produce vapor of the present composition at a relatively elevated pressure. Generally, the step of compressing the vapor results in the addition of heat to the vapor, thus causing an increase in the temperature of the relatively high-pressure vapor. Preferably, the present methods include removing from this relatively high temperature, high pressure vapor at least a portion of the heat added by the evaporation and compression steps. The heat removal step preferably includes condensing the high temperature, high-pressure vapor while the vapor is in a relatively high-pressure condition to produce a relatively high-pressure liquid comprising a composition of the present invention. This relatively high-pressure liquid preferably then undergoes a nominally isoenthalpic reduction in pressure to produce a relatively low temperature, low-pressure liquid. In such embodiments, it is this reduced temperature refrigerant liquid which is then vaporized by heat transferred from the body or fluid to be cooled.

In another process embodiment of the invention, the compositions of the invention may be used in a method for producing heating which comprises condensing a refrigerant comprising the compositions in the vicinity of a liquid or body to be heated. Such methods, as mentioned hereinbefore, frequently are reverse cycles to the refrigeration cycle described above.

EXAMPLES

The following examples are provided for the purpose of illustrating the present invention but without limiting the scope thereof.

Example 1 Medium Temperature System with HFC-32 and CF3I

The capacity of a heat transfer composition (and a refrigerant in particular) represents the cooling or heating capacity and provides some measure of the capability of a compressor to pump quantities of heat for a given volumetric flow rate of refrigerant. In other words, given a specific compressor, a refrigerant with a higher capacity will deliver more cooling or heating power.

A refrigeration/air conditioning cycle system is simulated or provided with a condenser temperature is about 40° C., an evaporator temperature of about 2° C., a superheat of about 10° C., and a sub-cool temperature of about 5° C., and a compressor efficiency of 0.7, which would normally be considered typical “medium temperature” conditions. Several compositions of the present invention are simulated and/or tested based on a first component consisting of HFC-32, a second component consisting of CF3I and one of a series of third components as described above. For each third component, the relative concentrations of all three components which substantially match the capacity of R-410A under the conditions mentioned above is determined. A curve of the various concentrations of each component for which the capacity substantially matches that of R0410A is then drawn or simulated (visually, mathematically, or a combination of each). An asterix is then placed on the curve to signify those compositions having a GWP of 1000 or less and a diamond is placed on the curve to signify those compositions having a GWP of greater than 1000. This procedure is repeated for all third component compounds identified above and for the second component compound HFO-1225ye-Z. One example of a “tool” for selecting a refrigerant for this system is thus developed and is presented as the chart in FIG. 1. The chart in FIG. 1 is analyzed to identify compositions which fall on or about the curves and for which GWP is less than about 1000. This identification is preferably preceded or followed by an analysis of the flammability of the compositions, and then a selection is made of a composition to use as an original component of such system or as a replacement or retrofit to such an existing system.

Example 2 Medium Temperature System with HFC-32/CO2 and CF3I

Example 1 is repeated except that the first component of the heat transfer composition consists of 3 percent by weight of CO2 and 97 percent by weight of HFC-32 and that the refrigerant whose capacity is to be matched is R-410A. The chart in FIG. 2 is developed and analyzed to identify compositions which fall on or about the curves and for which GWP is less than about 1000. This identification is preferably preceded or followed by an analysis of the flammability of the compositions, and then a selection is made of a composition to use as an original component of such system or as a replacement or retrofit to such an existing system.

Example 3 Medium Temperature System with HFC-32/CO2 and CF3I

Example 1 is repeated except that the first component of the heat transfer composition consists of 1 percent by weight of CO2 and 99 percent by weight of HFC-32 and that the refrigerant whose capacity is to be matched is R-410A. The chart in FIG. 3 is developed and analyzed to identify compositions which fall on or about the curves and for which GWP is less than about 1000. This identification is preferably preceded or followed by an analysis of the flammability of the compositions, and then a selection is made of a composition to use as an original component of such system or as a replacement or retrofit to such an existing system.

Example 4 Low Temperature System with HFC-32/CO2 and CF3I

Example 1 is repeated except that the first component of the heat transfer composition consists of 3 percent by weight of CO2 and 99 percent by weight of HFC-32, and that the refrigerant whose capacity is to be matched is R-410A, and that the conditions are a condenser temperature of about 45° C., an evaporator temperature of about −34° C., a superheat of about 10° C., and a sub-cool temperature of about 5° C., and a compressor efficiency of 0.7, which would normally be considered typical “low temperature” conditions. The chart in FIG. 4 is developed and analyzed to identify compositions which fall on or about the curves and for which GWP is less than about 1000. This identification is preferably preceded or followed by an analysis of the flammability of the compositions, and then a selection is made of a composition to use as an original component of such system or as a replacement or retrofit to such an existing system.

Example 5 Low Temperature System with HFC-32/CO2 and CF3I

Example 1 is repeated except that the first component of the heat transfer composition consists of 1 percent by weight of CO2 and 99 percent by weight of HFC-32, and that the refrigerant whose capacity is to be matched is R-410A, and that the conditions are a condenser temperature of about 45° C., an evaporator temperature of about −34° C., a superheat of about 10° C., and a sub-cool temperature of about 5° C., and a compressor efficiency of 0.7, which would normally be considered typical “low temperature” conditions. The chart in FIG. 5 is developed and analyzed to identify compositions which fall on or about the curves and for which GWP is less than about 1000. This identification is preferably preceded or followed by an analysis of the flammability of the compositions, and then a selection is made of a composition to use as an original component of such system or as a replacement or retrofit to such an existing system.

Example 6 Medium Temperature System with HFC-32 and HFO-1225

A refrigeration/air conditioning cycle system is simulated or provided with a condenser temperature is about 40° C., an evaporator temperature of about 2° C., a superheat of about 10° C., and a sub-cool temperature of about 5° C., and a compressor efficiency of 0.7, which would normally be considered typical “medium temperature” conditions. Several compositions of the present invention are simulated and/or tested based on a first component consisting of HFC-32, a second component consisting of HFO-1225ye-Z and one of a series of third components as described above. For each third component, the relative concentrations of all three components which substantially match the capacity of R-410A under the conditions mentioned above is determined. A curve of the various concentrations of each component for which the capacity substantially matches that of R0410A is then drawn or simulated (visually, mathematically, or a combination of each). An asterix is then placed on the curve to signify those compositions having a GWP of 1000 or less and a diamond is placed on the curve to signify those compositions having a GWP of greater than 1000. This procedure is repeated for all third component compounds identified above and for the second component compound CF3I. One example of a “tool” for selecting a refrigerant for this system is thus developed and is presented as the chart in FIG. 6. The chart in FIG. 6 is analyzed to identify compositions which fall on or about the curves and for which GWP is less than about 1000. This identification is preferably preceded or followed by an analysis of the flammability of the compositions, and then a selection is made of a composition to use as an original component of such system or as a replacement or retrofit to such an existing system.

Example 7 Low Temperature System with HFC-32 and HFO-1225

Example 6 is repeated except that the conditions are a condenser temperature of about 45° C., an evaporator temperature of about −34° C., a superheat of about 10° C., and a sub-cool temperature of about 5° C., and a compressor efficiency of 0.7, which would normally be considered typical “low temperature” conditions. The chart in FIG. 7 is developed and analyzed to identify compositions which fall on or about the curves and for which GWP is less than about 1000. This identification is preferably preceded or followed by an analysis of the flammability of the compositions, and then a selection is made of a composition to use as an original component of such system or as a replacement or retrofit to such an existing system.

Example 8 Medium Temperature System with HFC-32/CO2 and HFO-1225

Example 6 is repeated except that the first component of the heat transfer composition consists of 3 percent by weight of CO2 and 97 percent by weight of HFC-32. The chart in FIG. 8 is developed and analyzed to identify compositions which fall on or about the curves and for which GWP is less than about 1000. This identification is preferably preceded or followed by an analysis of the flammability of the compositions, and then a selection is made of a composition to use as an original component of such system or as a replacement or retrofit to such an existing system.

Example 9 Medium Temperature System with HFC-32/CO2 and HFO-1225

Example 6 is repeated except that the first component of the heat transfer composition consists of 1 percent by weight of CO2 and 97 percent by weight of HFC-32. The chart in FIG. 9 is developed and analyzed to identify compositions which fall on or about the curves and for which GWP is less than about 1000. This identification is preferably preceded or followed by an analysis of the flammability of the compositions, and then a selection is made of a composition to use as an original component of such system or as a replacement or retrofit to such an existing system.

Example 10 Low Temperature System with HFC-32/CO2 and HFO-1225

Example 6 is repeated except that the first component of the heat transfer composition consists of 3 percent by weight of CO2 and 97 percent by weight of HFC-32 and that the conditions are a condenser temperature of about 45° C., an evaporator temperature of about −34° C., a superheat of about 10° C., and a sub-cool temperature of about 5° C., and a compressor efficiency of 0.7, which would normally be considered typical “low temperature” conditions. The chart in FIG. 10 is developed and analyzed to identify compositions which fall on or about the curves and for which GWP is less than about 1000. This identification is preferably preceded or followed by an analysis of the flammability of the compositions, and then a selection is made of a composition to use as an original component of such system or as a replacement or retrofit to such an existing system.

Example 11 Low Temperature System with HFC-32/CO2 and HFO-1225

Example 6 is repeated except that the first component of the heat transfer composition consists of 1 percent by weight of CO2 and 99 percent by weight of HFC-32 and that the conditions are a condenser temperature of about 45° C., an evaporator temperature of about −34° C., a superheat of about 10° C., and a sub-cool temperature of about 5° C., and a compressor efficiency of 0.7, which would normally be considered typical “low temperature” conditions. The chart in FIG. 11 is developed and analyzed to identify compositions which fall on or about the curves and for which GWP is less than about 1000. This identification is preferably preceded or followed by an analysis of the flammability of the compositions, and then a selection is made of a composition to use as an original component of such system or as a replacement or retrofit to such an existing system.

Example 12 Low Temperature System with HFC-32 and CF3I

Example 1 is repeated except that the conditions are a condenser temperature of about 45° C., an evaporator temperature of about −34° C., a superheat of about 10° C., and a sub-cool temperature of about 5° C., and a compressor efficiency of 0.7, which would normally be considered typical “low temperature” conditions. The chart in FIG. 12 is developed and analyzed to identify compositions which fall on or about the curves and for which GWP is less than about 1000. This identification is preferably preceded or followed by an analysis of the flammability of the compositions, and then a selection is made of a composition to use as an original component of such system or as a replacement or retrofit to such an existing system.

Claims

1. A heat transfer composition comprising:

(a) a first component comprising difluoromethane (R-32);
(b) a second component selected from group consisting of CF3I, 1,2,3,3,3-pentafluoropropene (HFO-1225), and combinations of these;
(c) and optionally at least one third component selected from the group consisting of fluorinated C2-C3 compounds.

2. The heat transfer composition of claim 1 wherein said second component is a flammability reducing agent.

3. The heat transfer composition of claim 1 wherein said third component is present and is selected from the group consisting of fluorinated ethanes, fluorinated alkenes, and combinations of any two or more of these.

4. The heat transfer composition of claim 3 wherein said third component is selected from the group consisting of monofluoroethane (HFC-161), difluoroethane (HFC-152a), trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC-134a), pentafluoroethane (HFC-125), at least one fluoroalkene of Formula I:

where each R is independently Cl, F, Br, I or H
R′ is (CR2)nY,
Y is CRF2
and n is 0 or 1, and combinations of any two or more of these.

5. The heat transfer composition of claim 4 wherein Y is CF3.

6. The heat transfer composition of claim 5 wherein at least one R on the unsaturated terminal carbon is H.

7. The heat transfer composition of claim 6 wherein n is 0.

8. The heat transfer composition of claim 4 wherein Y is CF3 and n is 0.

9. The heat transfer composition of claim 3 wherein said at least one fluoroalkene comprises at least one tetrafluoropropene (HFO-1234).

11. The heat transfer composition of claim 9 wherein said at least one tetrafluoropropene is HFO-1234ze.

12. The heat transfer composition of claim 1 wherein said first component, said second component and said third component, when present, are present in amounts effective to provide the heat transfer composition with a capacity that is not substantially less than the capacity in low temperature applications of at of at least one of R-22, R-404A, R-407C, R-410A, or R-507, and combinations of any two or more of these.

13. The heat transfer composition of claim 1 wherein said first component, said second component and said third component, when present, are present in amounts effective to provide the heat transfer composition with a capacity that is not substantially less than the capacity in medium temperature applications of at least one of R-22, R-404A, R-407C, R-410A, or R-507, and combinations of any two or more of these.

14. A method of transferring heat to or from a fluid or body comprising causing a phase change in a composition of claim 1 and exchanging heat with said fluid or body during said phase change.

15. The method according to claim 12 wherein said HFO-1234ze comprises at least about 90% by weight trans-1,3,3,3-tetrafluoropropene (transHFO-1234ze).

16. The method according to claim 12 wherein said HFO-1234ze comprises at least about 95% by weight trans-1,3,3,3-tetrafluoropropene (transHFO-1234ze).

17. The method according to claim 12 wherein said HFO-1234ze comprises at least about 97% by weight trans-1,3,3,3-tetrafluoropropene (transHFO-1234ze).

18. A refrigeration system comprising a heat transfer composition of claim 1.

19. The refrigeration system of claim 18 selected from the group consisting of automotive air conditioning systems, residential air conditioning systems, commercial air conditioning systems, residential refrigerator systems, residential freezer systems, commercial refrigerator systems, commercial freezer systems, chiller air conditioning systems, chiller refrigeration systems, heat pump systems, and combinations of two or more of these.

20. A method of selecting a composition for use in an existing heat transfer system, the method comprising:

a) analyzing the existing heat transfer system in a manner sufficient to permit approximation of the capacity of the fluid used in the existing heat transfer system;
b) approximating the capacity of two or more heat transfer compositions, said two or more compositions comprising: (i) a first component comprising difluoromethane (R-32); (ii) a second component selected from group consisting of CF3I, 1,2,3,3,3-pentafluoropropene (HFO-1225), and combinations of these; (iii) and optionally at least one third component selected from the group consisting of fluorinated C2-C3 compounds; and
c) selecting at least one of said two or more of heat transfer compositions for use in the existing heat transfer system.
Patent History
Publication number: 20080121837
Type: Application
Filed: Jul 6, 2007
Publication Date: May 29, 2008
Applicant: Honeywell International, Inc. (Morristown, NJ)
Inventors: Rajiv R. Singh (Getzville, NY), Ian Shankland (Randolph, NJ), Ryan Hulse (Getzville, NY)
Application Number: 11/773,959
Classifications
Current U.S. Class: Vaporization, Or Expansion, Refrigeration Or Heat Or Energy Exchange (252/67)
International Classification: C09K 5/02 (20060101);